The membrane-associated protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1 MDR/TAP MRP ALD OABP GCN20 White). This protein is a member of the MDR/TAP subfamily. Members of the MDR/TAP subfamily are involved in multidrug resistance as well as antigen presentation. The function of this half-transporter has not yet been determined; however it may involve the compartmentalization and transport of heme as well as peptides from the mitochondria to the nucleus and cytosol. This protein may also play a role in the transport of phospholipids into mitochondrial membranes. [provided by RefSeq Jul 2008]